Controlling device for an escape wheel

ABSTRACT

A controlling device for an escape wheel supported between a bridge and a plate, the controlling device including a resilient member provided on the bridge or plate and positioned to apply force axially to the escape wheel. The resilient member may be UShaped and positioned to apply force axially to the escape wheel and a second wheel.

United States Patent 1 1 3,695,033 Fujimori 45 Oct, 3, 1972 [54] CONTROLLING DEVICE FOR AN 3,609,961 10/1971 Tsuzuki ..58/125 R ESCAPE WHEEL 1,976,181 10/ 1934 Marti ..58/ 140 A 2,456,071 12/1948 Marchand ..58/140 A --lr55t9iwMFul9P99t9Yv3il53fim- 2,618,118 11/1952 Harris et a1 ..58/59 Assignee; Kabishiki Kaisha Suwa seikosha, Marti 6t A Tokyo, Ja an 2,780,910 2/ 1957 Muffley ..58/107 2,977,751 4/1961 Thrasher, Jr. ..58/ 107 [22] Filed: June 3, 1971 3,117,411 1/1964 Knauer ..58/107 [2]] 'Appl' 149599 Primary Examiner- Richard B. Wilkinson Assistant Examiner-Stanley A. Wal [30] Foreign Application p i i Data Attorney-Blum, Moscovitz, Friedman & Kaplan June 9, 1970 Japan ..45/56291 57 ABSTRACT 52 US. Cl. ..58/116 R 58/125 R A device an escape wheel SPPmted [51] Int CL I 15/00 between a bridge and a plate, the controlling device [58] Field 140 R 140 A including a resilient member provided on the bridge or 58/l07 plate and positioned to apply force axially to the escape wheel. The resilient member may be U-Shaped and positioned to apply force axially to the escape [56] References Cited wheel and a second wheel.

UNITED STATES PATENTS 3 Claims 9 Drawing Figures 3,408,810 11/1968 Meitinger ..58/125 R FIG. 3

SHEET 3 0F 5 FIG. 5

PR/Or? 427- FIG-6' PATENIEDnm m2- 3.695.033

.snwsnrs FIG-9' v v CONTROLLING DEVICE FOR AN ESCAPE WHEEL BACKGROUND OF THE INVENTION This invention relates'to a controlling device for the escape wheel of an electric watch. In a conventional mechanical watch, force is applied to an escapement and a regulator through the gear train from a power source such as a spring, the spring being run down by the regular oscillation of a regulator. The regular rotation of the gear train is utilized as the time indication. On the other hand, in an electric watch, an escapement and a regulator serve to drive the gear train, so torque is not applied to the gear train except when an escape wheel is operating.

In a mechanical watch, due to the torque applied by the power source, an escape wheel applies rotational power to a pallet fork so that the escape wheel and pallet fork can keep the geometrical relation at both operating time and non-operating time. Thus, the escape wheel and pallet fork are controlled in a determined position. This drawing operation cannot be provided in an electric watch, so it is necessary to provide a construction which provides the drawing operation separately on an escape wheel and pallet fork.

SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, a device for controlling an escape wheel is provided, said device including a resilient member, for applying an axial force to said escape wheel. The escape wheel is mounted between a bridge and a plate, and said resilient member is mounted on one of said bridge and plate.

Accordingly, it is an object of this invention to provide a controlling device for an escape wheel particularly adapted for electric watches which utilizes a minimum of parts, is inexpensiveto manufacture, and performs the control function without impeding the precision of the watch.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIGS. 1, 3 and 5 are plan views of conventional controllingdevices for escape wheels;

FlGS. 2, 4 and 6 are cross-sectional views of said devices;

FIGS. 7 and 8 are cross-sectional views of one embodiment of the present invention; and

HO. 9 is a plan view of one embodiment of the present invention.

' DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, an escape wheel 1 and a friction disc 2 are fixed coaxially to a shaft 3, which is supported by a plate 4 and a bridge 5. A resilient member 6, an edge of which is fixed to said plate 4 or the bridge 5, is pressedagainst said friction disc 2 radially on said shaft 3, to generate frictional torque. Due to this frictional torque, the controlling position of the escape wheel is determined. In this method, after an escape wheel is inserted between the plate 4 and the bridge 5, it is necessary to assemble the resilient member 6. And because said resilient member 6 is concealed completely under the bridge 5, the resilient member 6 must be assembled or regulated through a peeping hole in the bridge 5 or a gap between the plate 4 and the bridge 5. Accordingly, assembly is very difficult, the position or shape of the resilient member is very hard to modify, frictional torque is not stabilized, and regulating takes much time.

Moreover, the electric circuit of an electric timepiece needs much space, so the space for the gear train is reduced, and it is very difficult to provide a stable resilient member. It is especially difficult to provide 'a resilient member wherein the lateral pressure thereof does not impede the engagement between the escape wheel and the pallet fork and between the escape wheel and the gear train. v

In another prior art method, wherein the controlling position of the escape wheel is determined by the attraction of a magnet, the frequency of the balance wheel is equal to the advancing step of a second hand. That is to say, during a two cycles of frequency of a balance wheel, an escape wheel is driven by one-half pitch, the loading on an escape wheel and a regulator as a driving source is decreased, and the precision of the watch is hightened.

This method is shown in FIGS. 3 and 4, wherein an escape wheel 1 and a wheel 7, said wheel having a number of teeth equal to a multiple of the teeth of said escape wheel 1, are fixed coaxially to a shaft 3. A magnet 8, which is fixed to a plate 4, is under the teeth edge of said wheel 7, and attracts the teeth of the wheel 7 due to the magnetic force and controls the escape wheel in a determined position.

In FIGS. 5 and 6, an escape wheel 1 itself is formed of a material having strong magnetism. Moreover, track-shaped holes in a number equal to twice the number of teeth of the escape wheel are provided on the limb part of said escape wheel 1 at regular intervals. This escape wheel is fixed to a shaft 3.

A magnet 8, which is fixed to a plate 4, is placed under the track-shaped holes of said escape wheel 1 and attracts the bone shaped part between the track holes. Thus an escape wheel is controlled in a determined position.

However, the above-described prior art arrangement has the following defects. As described above, because material having strong magnetism is used in the wheel or escape wheel, they are liable to be affected by an external magnetic field or the magnet for driving the oscillator. For this reason, the functions of an escape wheel and a regulator are impeded. This defect is sought to be avoided by the provision of an expensive magnetic shield. Moreover, heat treatment is necessary for elevating the magnetic characteristics of said escape wheel or wheel. Thus, manufacturing is dif ficult, and the processing steps are increased. Since special materials such as a magnet and a strong magnetic material are used and the number of parts is increased, the cost is great.

In determining the controlling position of an escape wheel, if all parts do not control certainly in the determined positions due to magnetic force, engagement of the escape wheel and a pallet fork is impeded, and what is worse, the watch is stopped. Therefore, the relationship between the magnet and escape wheel, including the error between gears of the wheel and escape wheel, shape error, and error of eccentricity, must be adjusted and positioned with scrupulous care. Since so much labor and adjusting operations are necessary, manufacturing of this arrangement is troublesome.

' The arrangement according to the invention eliminates those defects. The object of this invention is to simplify the controlling device and satisfy the determining of controlling position of an escape wheel.

As shown in FIG. 7, an escape wheel 1 is fixed to a shaft 3. Its lower pivot is supported by a jewel 9 fixed to a plate 4, and its upper pivot is supported by a jewel 10 fixed to a bridge 5. A holding spring 6 fixedto the bridge 5 by a screw 11 applies axial force to the top of said shaft'3 projecting from the jewel 10 ."The controlling position of the escape wheel is determined by the brake torque generated bythe friction between the jewel 9 and the lower part of said shaft 3.

In FIG. 8, the controlling position of an escape wheel is determined by applying axial force upwardly to the pinion part of the shaft 3.

The jewels 9 and 10 are formed of low frictional stable material. A spot contact or the like is maintained between the escape wheel 3 and the holding spring 6. The contact part between jewels 9, 10 and said shaft 3 is made minimum. Thus, if the spring force is increased, brake torque is not increased comparatively. Therefore, stable brake torque is obtained.

In the above described device, the holding spring can be assembled, during or after the escape wheel is assembled into the plate or bridge. Accordingly, assembly is made very simple and easy. In addition, it is unnecessary to adjust the shape or the position of the holding spring through the gap between the plate and bridge or a peeping hole in a bridge. Therefore, adjusting is made easier, the spring force of the holding spring is stable, and stable brake torque on an escape wheel is obtainable.

Since the holding spring is placed above or under the gear train, space is not much restricted, the shape of the spring may be made stable, and the change in spring force because of the dispersion of the spring is decreased. Moreover, the controlling force is applied in an axial direction along a shaft, so engagement between the escape wheel and the pallet fork or the escape wheel and the gear train is never impeded. The abovedescribed defects in the prior art are also avoided.

As described above, the characteristics of the arrangement according to the invention are that the frequency of the balance wheel is made equal to the advancing step of the second hand,'the-precision of the watch is not impeded, the determining function of the controlling position is made stable and sufiicient by simplifying the controlling structure of the escape wheel, assembly and adjustment are effected easily, and the influence upon the function due to the dispersion of the st cture c be decreased.

A further eature o the arrangement according to the invention is shown in FIG. 9. Torque is impassable in many of the gear trains of an electric watch, and therefore a holding spring 12 must be provided to hold down the second wheel shaft, on which the second wheel 13 is mounted, at every advance of a second hand so that the shake of a second hand because of the backlash of said second wheel is prevented. However, as shown in FIG. 9, if the holding spring 12 is made in a body with the springs of the escape wheel 1 of the arrangement according to the invention, the controlling operation can be effected by one part.

It will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. A controlling device for eliminating operation errors in timepieces comprising a bridge; a plate; a balance wheel; a gear train; an escapement intermediate said balance wheel and said gear train and including a first shaft mounted between said bridge and plate and an escape wheel carried by said first shaft; a second shaft mounted between said bridge and plate; a second wheel carried by said second shaft; a U-shaped resilient member having a pair of substantially identical resilient arms and a base portion joining said arm; and means for mounting said resilient member at the base portion thereof on one of said bridge and plate positioned so that one of said resilient member arms applies an axial force to said first shaft and the other of said resilient member arms applies an axial force to said second shaft.

2. A controlling device as recited in claim 1, wherein said resilient member arms respectively engage the ends of said first and second shaft.

3. A controlling device as recited in claim 1, each of said first and second shafts including a pinion portion, said resilient member arms respectively engaging an end of the pinion portion associated with each of said first and second sh 

1. A controlling device for eliminating operation errors in timepieces comprising a bridge; a plate; a balance wheel; a gear train; an escapement intermediate said balance wheel and said gear train and including a first shaft mounted between said bridge and plate and an escape wheel carried by said first shaft; a second shaft mounted between said bridge and plate; a second wheel carried by said second shaft; a U-shaped resilient member having a pair of substantially identical resilient arms and a base portion joining said arm; and means for mounting said resilient member at the base portion thereof on one of said bridge and plate positioned so that one of said resilient member arms applies an axial force to said first shaft and the other of said resilient member arms applies an axial force to said second shaft.
 2. A controlling device as recited in claim 1, wherein said resilient member arms respectively engage the ends of said first and second shaft.
 3. A controlling device as recited in claim 1, each of said first and second shafts including a pinion portion, said resilient member arms respectively engaging an end of the pinion portion associated with each of said first and second shafts. 